/*

 * task_smpl.c - example of a task sampling another one using a randomized sampling period

 *

 * Copyright (c) 2009 Google, Inc

 * Contributed by Stephane Eranian <eranian@gmail.com>

 *

 * Based on:

 * Copyright (c) 2003-2006 Hewlett-Packard Development Company, L.P.

 * Contributed by Stephane Eranian <eranian@hpl.hp.com>

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies

 * of the Software, and to permit persons to whom the Software is furnished to do so,

 * subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in all

 * copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,

 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A

 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF

 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE

 * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 */

#include <sys/types.h>

#include <linux/types.h>

#include <stdio.h>

#include <stdlib.h>

#include <stdarg.h>

#include <unistd.h>

#include <errno.h>

#include <string.h>

#include <signal.h>

#include <getopt.h>

#include <setjmp.h>

#include <sys/wait.h>

#include <sys/poll.h>

#include <sys/mman.h>

#include <locale.h>

#include <sys/ioctl.h>

#include <err.h>

#include "perf_util.h"

#define SMPL_PERIOD	240000000ULL

typedef struct {

	int opt_no_show;

	int opt_inherit;

	int mem_mode;

	int branch_mode;

	int cpu;

	int mmap_pages;

	char *events;

	FILE *output_file;

} options_t;

static jmp_buf jbuf;

static uint64_t collected_samples, lost_samples;

static perf_event_desc_t *fds;

static int num_fds;

static options_t options;

static struct option the_options[]={

	{ "help", 0, 0,  1},

	{ "no-show", 0, &options.opt_no_show, 1},

	{ 0, 0, 0, 0}

};

static char *gen_events = "cycles,instructions";

static void

cld_handler(int n)

{

	longjmp(jbuf, 1);

}

int

child(char **arg)

{

	execvp(arg[0], arg);

	/* not reached */

	return -1;

}

struct timeval last_read, this_read;

static void

process_smpl_buf(perf_event_desc_t *hw)

{

	struct perf_event_header ehdr;

	int ret;

	for(;;) {

		ret = perf_read_buffer(hw, &ehdr, sizeof(ehdr));

		if (ret)

			return; /* nothing to read */

		if (options.opt_no_show) {

			perf_skip_buffer(hw, ehdr.size - sizeof(ehdr));

			continue;

		}

		switch(ehdr.type) {

			case PERF_RECORD_SAMPLE:

				collected_samples++;

				ret = perf_display_sample(fds, num_fds, hw - fds, &ehdr, options.output_file);

				if (ret)

					errx(1, "cannot parse sample");

				break;

			case PERF_RECORD_EXIT:

				display_exit(hw, options.output_file);

				break;

			case PERF_RECORD_LOST:

				lost_samples += display_lost(hw, fds, num_fds, options.output_file);

				break;

			case PERF_RECORD_THROTTLE:

				display_freq(1, hw, options.output_file);

				break;

			case PERF_RECORD_UNTHROTTLE:

				display_freq(0, hw, options.output_file);

				break;

			default:

				printf("unknown sample type %d\n", ehdr.type);

				perf_skip_buffer(hw, ehdr.size - sizeof(ehdr));

		}

	}

}

int

mainloop(char **arg)

{

	static uint64_t ovfl_count; /* static to avoid setjmp issue */

	struct pollfd pollfds[1];

	sigset_t bmask;

	int go[2], ready[2];

	size_t pgsz;

	size_t map_size = 0;

	pid_t pid;

	int status, ret;

	int i;

	char buf;

	if (pfm_initialize() != PFM_SUCCESS)

		errx(1, "libpfm initialization failed\n");

	pgsz = sysconf(_SC_PAGESIZE);

	map_size = (options.mmap_pages+1)*pgsz;

	/*

	 * does allocate fds

	 */

	ret  = perf_setup_list_events(options.events, &fds, &num_fds);

	if (ret || !num_fds)

		errx(1, "cannot setup event list");

	memset(pollfds, 0, sizeof(pollfds));

	ret = pipe(ready);

	if (ret)

		err(1, "cannot create pipe ready");

	ret = pipe(go);

	if (ret)

		err(1, "cannot create pipe go");

	/*

	 * Create the child task

	 */

	if ((pid=fork()) == -1)

		err(1, "cannot fork process\n");

	if (pid == 0) {

		close(ready[0]);

		close(go[1]);

		/*

		 * let the parent know we exist

		 */

		close(ready[1]);

		if (read(go[0], &buf, 1) == -1)

			err(1, "unable to read go_pipe");

		exit(child(arg));

	}

	close(ready[1]);

	close(go[0]);

	if (read(ready[0], &buf, 1) == -1)

		err(1, "unable to read child_ready_pipe");

	close(ready[0]);

	fds[0].fd = -1;

	if (!fds[0].hw.sample_period)

		errx(1, "need to set sampling period or freq on first event, use :period= or :freq=");

	for(i=0; i < num_fds; i++) {

		if (i == 0) {

			fds[i].hw.disabled = 1;

			fds[i].hw.enable_on_exec = 1; /* start immediately */

		} else

			fds[i].hw.disabled = 0;

		if (options.opt_inherit)

			fds[i].hw.inherit = 1;

		if (fds[i].hw.sample_period) {

			/*

			 * set notification threshold to be halfway through the buffer

			 */

			fds[i].hw.wakeup_watermark = (options.mmap_pages*pgsz) / 2;

			fds[i].hw.watermark = 1;

			fds[i].hw.sample_type = PERF_SAMPLE_IP|PERF_SAMPLE_TID|PERF_SAMPLE_READ|PERF_SAMPLE_TIME|PERF_SAMPLE_PERIOD;

			/*

			 * if we have more than one event, then record event identifier to help with parsing

			 */

			if (num_fds > 1)

				fds[i].hw.sample_type |= PERF_SAMPLE_IDENTIFIER;

			fprintf(options.output_file,"%s period=%"PRIu64" freq=%d\n", fds[i].name, fds[i].hw.sample_period, fds[i].hw.freq);

			fds[i].hw.read_format = PERF_FORMAT_SCALE;

			if (fds[i].hw.freq)

				fds[i].hw.sample_type |= PERF_SAMPLE_PERIOD;

			if (options.mem_mode)

				fds[i].hw.sample_type |= PERF_SAMPLE_WEIGHT | PERF_SAMPLE_DATA_SRC | PERF_SAMPLE_ADDR;

			if (options.branch_mode) {

				fds[i].hw.sample_type |= PERF_SAMPLE_BRANCH_STACK;

				fds[i].hw.branch_sample_type = PERF_SAMPLE_BRANCH_ANY;

			}

		}

		/*

		 * we are grouping the events, so there may be a limit

		 */

		fds[i].fd = perf_event_open(&fds[i].hw, pid, options.cpu, fds[0].fd, 0);

		if (fds[i].fd == -1) {

			if (fds[i].hw.precise_ip)

				err(1, "cannot attach event %s: precise mode may not be supported", fds[i].name);

			err(1, "cannot attach event %s", fds[i].name);

		}

	}

	/*

	 * kernel adds the header page to the size of the mmapped region

	 */

	fds[0].buf = mmap(NULL, map_size, PROT_READ|PROT_WRITE, MAP_SHARED, fds[0].fd, 0);

	if (fds[0].buf == MAP_FAILED)

		err(1, "cannot mmap buffer");

	/* does not include header page */

	fds[0].pgmsk = (options.mmap_pages*pgsz)-1;

	/*

	 * send samples for all events to first event's buffer

	 */

	for (i = 1; i < num_fds; i++) {

		if (!fds[i].hw.sample_period)

			continue;

		ret = ioctl(fds[i].fd, PERF_EVENT_IOC_SET_OUTPUT, fds[0].fd);

		if (ret)

			err(1, "cannot redirect sampling output");

	}

	if (num_fds > 1 && fds[0].fd > -1) {

		for(i = 0; i < num_fds; i++) {

			/*

			 * read the event identifier using ioctl

			 * new method replaced the trick with PERF_FORMAT_GROUP + PERF_FORMAT_ID + read()

			 */

			ret = ioctl(fds[i].fd, PERF_EVENT_IOC_ID, &fds[i].id);

			if (ret == -1)

				err(1, "cannot read ID");

			fprintf(options.output_file,"ID %"PRIu64"  %s\n", fds[i].id, fds[i].name);

		}

	}

	pollfds[0].fd = fds[0].fd;

	pollfds[0].events = POLLIN;

	for(i=0; i < num_fds; i++) {

		ret = ioctl(fds[i].fd, PERF_EVENT_IOC_ENABLE, 0);

		if (ret)

			err(1, "cannot enable event %s\n", fds[i].name);

	}

	signal(SIGCHLD, cld_handler);

	close(go[1]);

	if (setjmp(jbuf) == 1)

		goto terminate_session;

	sigemptyset(&bmask);

	sigaddset(&bmask, SIGCHLD);

	/*

	 * core loop

	 */

	for(;;) {

		ret = poll(pollfds, 1, -1);

		if (ret < 0 && errno == EINTR)

			break;

		ovfl_count++;

		ret = sigprocmask(SIG_SETMASK, &bmask, NULL);

		if (ret)

			err(1, "setmask");

		process_smpl_buf(&fds[0]);

		ret = sigprocmask(SIG_UNBLOCK, &bmask, NULL);

		if (ret)

			err(1, "unblock");

	}

terminate_session:

	/*

	 * cleanup child

	 */

	wait4(pid, &status, 0, NULL);

	for(i=0; i < num_fds; i++)

		close(fds[i].fd);

	/* check for partial event buffer */

	process_smpl_buf(&fds[0]);

	munmap(fds[0].buf, map_size);

	perf_free_fds(fds, num_fds);

	fprintf(options.output_file,

		"%"PRIu64" samples collected in %"PRIu64" poll events, %"PRIu64" lost samples\n",

		collected_samples,

		ovfl_count, lost_samples);

	/* free libpfm resources cleanly */

	pfm_terminate();

	fclose(options.output_file);

	return 0;

}

static void

usage(void)

{

	printf("usage: task_smpl [-h] [--help] [-i] [-c cpu] [-m mmap_pages] [-M] [-b] [-o output_file] [-e event1,...,eventn] cmd\n");

}

int

main(int argc, char **argv)

{

	int c;

	setlocale(LC_ALL, "");

	options.cpu = -1;

	options.output_file=stdout;

	while ((c=getopt_long(argc, argv,"+he:m:ic:o:Mb", the_options, 0)) != -1) {

		switch(c) {

			case 0: continue;

			case 'e':

				if (options.events)

					errx(1, "events specified twice\n");

				options.events = optarg;

				break;

			case 'i':

				options.opt_inherit = 1;

				break;

			case 'm':

				if (options.mmap_pages)

					errx(1, "mmap pages already set\n");

				options.mmap_pages = atoi(optarg);

				break;

			case 'M':

				options.mem_mode = 1;

				break;

			case 'b':

				options.branch_mode = 1;

				break;

			case 'c':

				options.cpu = atoi(optarg);

				break;

			case 'o':

				options.output_file=fopen(optarg,"w");

				if (options.output_file==NULL) {

					printf("Invalid filename %s\n",

						optarg);

					exit(0);

				}

				break;

			case 'h':

				usage();

				exit(0);

			default:

				errx(1, "unknown option");

		}

	}

	if (argv[optind] == NULL)

		errx(1, "you must specify a command to execute\n");

	if (!options.events)

		options.events = strdup(gen_events);

	if (!options.mmap_pages)

		options.mmap_pages = 1;

	if (options.mmap_pages > 1 && ((options.mmap_pages) & 0x1))

		errx(1, "number of pages must be power of 2\n");

	return mainloop(argv+optind);

}